package com.ibs.action.login;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;


public class ShowImg extends HttpServlet {
    public ShowImg() {
        super();
    }

    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
    }

    public void service(HttpServletRequest request, HttpServletResponse response)
        throws IOException, ServletException {
        //    	设置页面不缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        HttpSession session = request.getSession(false);

        //    	 在内存中创建图象
        int width = 60;

        //    	 在内存中创建图象
        int height = 20;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);

        //    	 获取图形上下文
        Graphics g = image.getGraphics();

        //    	生成随机类
        Random random = new Random();

        //    	 设定背景色
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);

        //    	设定字体  
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        //    	画边框
        //    	g.setColor(new Color());
        //    	g.drawRect(0,0,width-1,height-1);

        //    	 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160, 200));

        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }

        //    	 取随机产生的认证码(4位数字)
        String sRand = "";

        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(random.nextInt(10));
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110),
                    20 + random.nextInt(110), 20 + random.nextInt(110))); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, (13 * i) + 6, 16);
        }

        //    	 将认证码存入SESSION
        session.setAttribute("rePassword", sRand);

        //    	 图象生效
        g.dispose();

        //    	 输出图象到页面
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }

    public Color getRandColor(int fc, int bc) { //给定范围获得随机颜色

        Random random = new Random();

        if (fc > 255) {
            fc = 255;
        }

        if (bc > 255) {
            bc = 255;
        }

        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);

        return new Color(r, g, b);
    }

    public String getServletInfo() {
        return "This is my default servlet created by Eclipse";
    }

    public void init() throws ServletException {
        // Put your code here
    }
}
